Aiming at evaluating hibiscus (Hibiscus rosa-sinensis) and sacarina as supplements for young bulls, four crossbred animalswere displayed in a Latin square experimental design. The following treatments were performed: 1 – 75% pasture + 25% concentrate; 2 – 50% pasture + 25% concentrate + 25% hibiscus; 3 – 50% pasture + 25% concentrate + 25% sacarina; and 4 – 25% pasture + 25% concentrate + 25% hibiscus + 25% sacarina. Diet composition, rumen fermentation, DM and CP degradation rates were evaluated. Rumen pH values varied from 5.82 to 6.98, for diets supplemented with hibiscus, at 9h post-feeding, and with sacarina, at the feeding moment. Ammonia N contents did not present great changes when only hibiscus or sacarina were added to the diet, but there was a significant effect when both were added P<0.001). Rumen SCFA concentrations were lower due to saccharine presence in the diet (P<0.01). Sacarina diet presented higher values for readily soluble fraction for DM and CP (P<0.01). Sacarina promoted a higher effect on DM degradation of total diets (P<0.05). Hibiscus and sacarina inclusion increased the degradation of diets for grazing young bulls (P<0.05). Including these feed to the concentrate, the rumen environment and functionality were improved. Thus, it is viable the partial replacement of concentrate by the tested feed.